Save Energy with Efficient Vacuum Pumps

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Save Energy with Efficient Vacuum Pumps System
Design Mukesh Kumar Gardner Denver Nash
IPPTA Zonal Seminar July 13-14, 2006 Chandigarh
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Topics

• Liquid Ring Vacuum Pump System
• Measurement and Monitoring of Vacuum Pump
  Efficiency
• Paper Machine Vacuum System Design
• Case Studies

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Liquid Ring Vacuum Pump System

• Liquid Ring Vacuum Pump
• Positive Displacement Technology
• Constant Volume, Variable Vacuum

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Liquid Ring Vacuum Pump System

• Common Characteristic of the Papermaking Process
  is Constant
• Change
• Changes in Paper Grade and Basis Weight
• Changes in Felt Permeability due to Felt Life
• Changes in Freeness
• and many other changes
• Liquid Ring Vacuum Pump System is Best Suited to
  Cope with
• above Changes

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Liquid Ring Vacuum Pump System
Changes in Paper Grade and Basis Weight
Liquid Ring Vacuum Pump System is Best Suited to
Deal with Changes Caused by Grade Variation
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Liquid Ring Vacuum Pump System
Changes in Felt Permeability
Liquid Ring Vacuum Pump System Will Be Able to
Achieve Good Results Despite the Changes in Felt
Permeability
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Liquid Ring Vacuum Pump System
Typical Mill Installation
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Liquid Ring Vacuum Pump System
Reliable and Efficient Overall Efficiencies
0.9 KW/CMM Most Common
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Measurement Monitoring of Vacuum Pump
Efficiency
Vacuum Pump Efficiency is Practically Expressed
in Terms of KW/CMM Fading Vacuum Level is
usually First Sign of Loss in Efficiency of
Vacuum Pump
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Measurement Monitoring of Vacuum Pump
Efficiency

• Capacity Testing
• Single or Dual Plate Orifice Method
• Manufacturer Test Methods HEI or Pneurop
• Video Inspections

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Measurement Monitoring of Vacuum Pump
Efficiency

• Single or Dual Plate Orifice Method
• Suitable for Mill Site
• Accuracy Level /- 10

Dual Plate
Single Plate
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Measurement Monitoring of Vacuum Pump
Efficiency
Manufacturers Test Methods HEI (USA) or Pneurope
(Europe)
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Measurement Monitoring of Vacuum Pump
Efficiency

• Video Inspections
• Very Useful for Inspecting Internal Condition of
  the Pump
• Generally Recommended for Large Pumps

Old Pump Showing Badly Worn-out Rotor Blade
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Paper Machine Vacuum System Design
Vacuum Piping Many Problem Often Originate in the
Piping System

• Key Design Considerations
• Recommended Velocities
• Wet Air 3500 FPM
• Dry Air 5500 FPM
• Use ACFM Values for Air Volume
• In case of Border Line Selection Use
• Next Higher Size Pipe
• Vacuum Piping Containing Liquid
• Must Run Slope Downward

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Paper Machine Vacuum System Design
Consequence of Incorrect Pipe Sizing Practical
Example Required Air Flow 3000 ACFM _at_ 15
Hg Vacuum Loss due to undersized pipe 5
Hg Vacuum Required at Vacuum Pump 20 Hg P1V1
P2V2 (ignoring temperature) P1 30-15 15 Hg A
(at application point) P2 30-20 10 Hg A (at
the pump) V2 3000 ACFM measured at Vacuum
Pump 15 x V1 10 x 3000 V1 (available at
application point) 2000 ACFM !!!!
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Paper Machine Vacuum System Design

• Pre-Separators
• Must Whenever Carryovers are Expected
• Help Reduce Electrical Load on Pump
• Prolong the Pump Life
• Help Reduce Pipe Size after the Separation
• Make Close Loop Re-Circulated Seal Water System
  Feasible
• Types
• Barometric Separator
• Separator Tank with Extraction Pump

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Paper Machine Vacuum System Design
Barometric Separator Used for Elevated
Applications L 1.13 ft x (Vacuum in inch Hg)
3 ft
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Paper Machine Vacuum System Design
Separator Tank with Extraction Pump Used for
Low Level Applications Example Bottom
Felts Require Centrifugal Pump with Very Low NPSH
Capabilities
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Paper Machine Vacuum System Design
Discharge System Discharge System is Often a
Neglected Area Overloading is a Common Problem in
Older Machines

• Key Design Considerations
• Recommended Velocities
• Wet Air 3500 FPM
• Separation 500 FPM
• Exhaust Air 8000 FPM
• Avoid Overloading as it
• creates back pressure
• excessive noise
• Back Pressure lt 1 Psig

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Case Study 1 Paper Mill in India
Production Capacity 60 TPD (Two Paper
Machines) Paper Grade Fine Paper Action Taken
Replacement of one Local Make Vacuum Pump by
Original Nash CL2002 Pump
in 1997 Duty Conditions Air Capacity 52
M3/min, Vacuum Level 450 mmHg Old Pump Details
Absorbed Power-63 KW, Motor-75 KW Nash CL 2002
Pump Details Absorbed Power- 47 KW, Motor- 55
KW Power Saving 25 Payback Period Less than
One Year This mill eventually replaced 5 Nos.
locally made pumps by Nash pumps gradually and
ordered Nash Pumps for new project in 2005.
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Case Study 2 Paper Mill in India
Production Capacity 150 TPD (Three Paper
Machines) Paper Grade Fine Paper Action Taken
Replacement of one Local Make Vacuum Pump by
Original Nash CL2002 Pump
in 2000 Duty Conditions Air Capacity 51
M3/min, Vacuum Level 510 mmHg Old Pump Details
Absorbed Power-65 KW, Motor-75 KW Nash CL 2002
Pump Details Absorbed Power- 48 KW Power
Saving 25 Payback Period Less than One
Year This mill eventually replaced 5 Nos. locally
made pumps of various sizes by Nash pumps
gradually and ordered Nash Pumps for new project
in 2006.
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Save Energy with Efficient Vacuum Pumps System
Design Mukesh Kumar Gardner Denver Nash
IPPTA Zonal Seminar July 13-14, 2006 Chandigarh